Light bar

ABSTRACT

A light bar may include a light head with chip-on-board (COB) light emitting diode (LED) and an optic component mounted adjacent to the COB LED. The light bar may comprise short and long center modules. The light bar may include a plurality of housing modules where each housing module includes a light head and a lens cover having a top portion that is substantially impervious to ultraviolet radiation, and a lens portion extending downward from the top portion in generally opposing relationship with the light head. The light bar may include a circuit board including a wire-to-board connector, and a light head including a wire-to-board connector mated with the wire-to-board connector on the circuit board to electrically connect the light head to the circuit board. The light head may include a holographic diffuser.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. Ser. No.12/566,017, filed Sep. 24, 2009, the entirety of which is incorporatedby reference herein.

FIELD OF THE INVENTION

The present invention generally relates to a light bar.

BACKGROUND

Warning light signals are generally used to clear the right of way or towarn oncoming motorists of potential moving or stationary hazards, suchas a vehicle that is stopped or a vehicle moving slower or faster thanthe rate of traffic. Warning light signals may also be used to providespecific directions to motorists, such as merge right or merge left orpull over. Some vehicles incorporate an arrow board or even a textmatrix display to generate warning light signals to direct traffic.

The use of emergency beacons is restricted by law in many jurisdictionsonly for responding to an emergency, initiating a traffic stop, bonafide training exercises, or when a specific hazard exists in the road.

SUMMARY

In one aspect, a light bar generally comprises a light head. The lighthead generally comprises a heat sink, and a circuit board in heattransfer communication with the heat sink. The circuit board has anelectrically conductive pathway. A chip-on-board (COB) light emittingdiode (LED) is mounted directly in contact with the circuit board suchthat heat generated by the COB LED when energized is transferred to thecircuit board. The COB LED has an LED chip electrically connected to theelectrically conductive pathway of the circuit board. An optic componentis mounted adjacent to the COB LED to capture light emitted by the COBLED when energized and to transmit the captured light. A transparenthousing encloses the plurality of light heads. A microcontroller iselectrically connected to the COB LED energize the LED chip so that thetransmitted light creates warning light signals when viewed by anobserver remote from the light bar.

In another aspect, a light bar generally comprises an elongate basehaving opposite longitudinal ends and a length extending between thelongitudinal ends. First and second outboard housing modules areremovably secured to the base adjacent to the opposite longitudinal endsof the base. At least one light head is disposed in each of the firstand second outboard housing modules. A short center module is removablysecured to the base between the first and second outboard housingmodules. The short center module has a length extending along the lengthof the base. At least one light head is disposed in the short centermodule. A long center module is removably secured to the base betweenthe first and second outboard housing modules. The long center modulehas a length extending along the length of the base. At least one lighthead is disposed in the long center module. The length of the longcenter module is greater than the length of the short center module.

In yet another aspect, a light bar generally comprises an elongate basehaving a length extending between opposite longitudinal ends, and aplurality of housing modules secured along the length of the base. Eachhousing module includes at least one light head, a platform on which theat least one light head is mounted, and a lens cover secured to theplatform. The lens cover has a top portion that is substantiallyimpervious to ultraviolet radiation, and a lens portion extendingdownward from the top portion in generally opposing relationship withthe at least one light head.

In another aspect, a light bar generally comprises a circuit boardincluding a wire-to-board connector, and a light head including awire-to-board connector mated with the wire-to-board connector on thecircuit board to electrically connect the light head to the circuitboard.

In yet another aspect, a light bar generally comprises a light headincluding a light source for selectively emitting light when energized,a collector adjacent to the light source to capture light emitted by thelight source when energized, a collimator adjacent to the collectoradapted to receive the captured light from the collector and transmitthe captured light as a substantially spatially uniform beam, and aholographic diffuser adjacent to the collimator for receiving thesubstantially spatially uniform beam from the collimator and fortransmitting the light in an output pattern which is horizontallydiverging at a horizontal angle which is greater than a horizontaldivergence angle of the substantially spatially uniform beam. Atransparent housing encloses the plurality of light heads. Amicrocontroller electrically connected to the light source energizes thelight source so that the transmitted light creates warning light signalswhen viewed by an observer remote from the light bar.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of one embodiment of a light bar including aplurality of light heads including chip-on-board light emitting diodes(COB LED);

FIG. 2 is an exploded view of one of the light heads in FIG. 1;

FIG. 3A is an enlarged perspective of an optic components and COB LEDsmounted on a circuit board of the light head in FIG. 2, each opticcomponent being associated with one COB LED;

FIG. 3B is an enlarged perspective of other embodiments of opticcomponents and COB LEDs mounted on a circuit board of a light head, eachoptic component being associated with four COB LED;

FIG. 4A is an enlarged perspective of the circuit board in FIG. 3A withthe optic components removed;

FIG. 4B is an enlarged perspective of the circuit board in FIG. 4A withthe optic components removed;

FIG. 5 is an enlarged, fragmentary cross-section of one of the opticcomponents, COB LED, and the circuit board in FIG. 3A, includingprotective material covering the COB LED;

FIG. 6 is similar to FIG. 5 except that the protective material coveringthe COB LED is removed;

FIG. 7 is a schematic diagram of one embodiment of a parallel-seriesconnection of four COB LEDs in each of three light defining areas;

FIG. 8 is a perspective of the light bar with a left outboard housingmodule exploded;

FIG. 9 is a cross-section through a housing module mounted on a base,the light heads being removed for ease of illustration;

FIG. 10 is an enlarged view of FIG. 9;

FIG. 11 is a perspective showing the base exploded from a mounting foot;

FIG. 12 is an enlarged perspective of an end portion of the base;

FIG. 13 is an enlarged perspective of the left outboard housing modulewith the lens cover and the light heads removed; and

FIG. 14 is an enlarged perspective of the left outboard housing modulewith the lens cover removed.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, one embodiment of a light bar 10 generallycomprises at least one light head 12 including at least onechip-on-board light emitting diode (COB LED 14), a housing, generallyindicated at 16, enclosing the light head 12, and a microcontroller 18(FIG. 13) in the housing to energize the COB LED 14 to create warninglight signals when viewed by an observer remote from the light bar 10.In the illustrated embodiment, the light bar 10 comprises a plurality ofsuch COB LED 14 light heads 12, although it is understood that the lightbar 10 may comprise a single COB LED 14 light head 12 without departingfrom the scope of the present invention. As will be explained in moredetail below, in one embodiment the microcontroller 18 is electricallyconnected to each of the light heads 12 so that the microcontrollercontrols each of the COB LEDs 14 in each of the light heads.

Referring to FIG. 2, each of the illustrated COB LED 14 light heads 12generally includes a heat sink 20, a circuit board 22 mounted on theheat sink 20 in thermal contact therewith, at least one defined lightemitting area 24 (FIG. 4) on the circuit board, including at least oneCOB LED 14, a driver 26 on the board in electrical communication withthe microcontroller 18 and the COB LED 14, and at least one opticcomponent 28 for capturing and transmitting light emitted from the lightemitting area(s). It is understood that in an alternate embodiment anindependent microcontroller may be mounted on each board 22 to controlthe COB LED(s) 14 in the corresponding light head 12. Themicrocontroller 18 is in communication with an input device, such as akeypad (not shown) controlled by an operator.

Each light head 12 may include any number of defined light emittingareas 24 on the circuit board 22. For example, in the illustratedembodiment the circuit board 22 is mounted in a vertical plane in thelight bar 10, and the board 22 includes three light emitting areas 24arranged as a horizontal linear array comprising a horizontal row of theCOB LEDs 14. In another embodiment, the circuit board 22 may be mountedin a vertical plane in the light bar 10, and a plurality of lightemitting areas 24 may be arranged in vertical linear array. In yetanother embodiment, the circuit board 22 may be mounted in a verticalplane in the light bar 10, and a plurality of light emitting areas 24may be arranged in a 2D array having at least two columns and two rows.

As stated above, each defined light emitting area 24 on the circuitboard 22 includes at least one COB LED 14. In the light head embodimentillustrated in FIGS. 3 and 4, each defined light emitting area 24includes one COB LED 14. In the illustrated embodiment in FIGS. 3A and4A, each defined light emitting area 24 includes a plurality (e.g., 4)COB LEDs 14. The type of light head 12 illustrated in FIGS. 3B and 4Bmay be used as a takedown light head. As an example and referring toFIG. 7, each COB LED 14 within the same light emitting area 24 may beelectrically connected to each other in parallel. Moreover, each lightemitting area 24 may be electrically connected to other light emittingareas in series. In the schematic illustrated in FIG. 7, the C1 may havea capacitance of about 0.001 μF, R1 may have a resistance of about 2.4Ohms, and R2 may have a resistance of about 2.4 Ohms. Other ways ofelectrically connecting the COB LEDs are possible without departing fromthe scope of the present invention. It is understood that each definedlight emitting area 24 may include any number of COB LEDs 14 withoutdeparting from the scope of the present invention.

Each COB LED 14 is mounted directly in contact with the circuit board 22such that heat generated by the COB LED 14 when energized is transferredto the circuit board 22. This heat is then transferred to the heat sink20. The light head(s) 12 may include thermal transfer layer 30 (FIG. 2),such as a thermal conducting plastic, for facilitating heat transferbetween the circuit board 22 and the heat sink 20. Each COB LED 14includes an LED chip or die 32 electrically connected to an electricallyconductive pathway (not shown) on the circuit board 22. The driver 26 onthe board 22 is electrically connected to each of LED chip 32 via theconductive pathway of the circuit board 22 for energizing the LED chips32. Referring to FIGS. 5 and 6, in the illustrated embodiment, each LEDchip 32 is electrically connected to the circuit board 22 by a bond wire38, although other ways of electrically connecting the LED chip 32 tothe circuit board 22 is within the scope of the invention. In oneexample, each bond wire 38 is bonded to the LED chip 32 by a wedge bond.The wedge-bonded bond wire 38 has a lower profile (i.e., the wireextends outward from the LED chip 32 at a smaller angle) than if thebond wire 38 was ball-bonded to the LED chip 32. This lower profileallows the optic component 28 to be positioned closer to the LED chip 32(e.g., within 0.005 inches) than if the bond wire 38 was ball-bonded tothe LED chip. The bond wire 38 may also be bonded to the electricallypathway 34 in the circuit board 22 by a wedge bond or another type ofbond.

Referring to FIGS. 2-4A and 5-6, the illustrated embodiment includesthree optic components 28, and each optic component is associated withone of the light emitting areas 24. Each optic component 28 in theillustrated embodiment generally includes an optical concentrator 40(e.g., a compound parabolic concentrator 40 (CPC), a flat platecollector (FPC), a V-trough concentrator, a parabolic troughconcentrator (PTC), a Fresnel lens concentrator, a conical concentrator,a paraboloidal concentrator, a compound elliptical concentrator (EPC), ahyperpolodial concentrator (trumpet concentrator), a sphericalconcentrator, or a pyramidical concentrator), an optical collector 42(e.g., a parabolic collector 42) and an optical collimator 44. Theoptical concentrator 40 has an input surface adjacent to thecorresponding LED chip(s) 32. In one embodiment (FIG. 5), the inputsurface of the concentrator 40 is in physical contact with and/orreceived in a transparent protective material 46 covering the LEDchip(s). The protective material 46 may include a transparent gel ortransparent epoxy material (e.g., LS-3354 silicon gel by NuSil ofCarpinteria, Calif.). In one example, for each LED chip the protectivematerial 46 has an index of refraction substantially matching the indexof refraction of the concentrator 40. In this example, the transparentprotective material 46 is applied to the bottom surface of theconcentrator 40 and the top surface of the COB LED 14. The transparentmaterial 46 preferably does not extend along the sides of the COB LED 14to the circuit board so that the material reflects most if not all ofthe light emitted from the COB LED into the concentrator 40 and does notscatter a significant amount of light radially outward. In anotherembodiment (FIG. 6), the concentrator 40 is not in contact with orreceived in the protective material 46. Instead, an air space 48 isbetween the input surface of the concentrator 40 and the LED chip(s),which may be a LED chip that emits white light. It is understood thatthe optic components 28 may be of other configurations and include otherelements. For example, the optic component 28 may not include an opticalconcentrator 40 without departing from the scope of the invention.

In one example, each optic component 28 is formed as a separate unit,and the optical concentrator 40 and the optical collector 42 of eachoptic component 28 are formed as a single, one-piece construction, wherethe inlet of the collector 42 is at the outlet of the concentrator 40.Each optic component 28 includes stands or legs 50 secured to thecircuit board 22 (such as by fasteners or screws 51) to mount the opticunit to the board 22 so that each optic component is associated with onelight emitting area 24. The concentrator 40 and the collector 42 may beformed from a homogenous material that is resistant to opticaldegradation due to UV radiation and heat cycling, such as acrylic orpolycarbonate (e.g., Makrolon® LED-2245 or LED-2045 polycarbonate resin,each by Bayer MaterialScience AG of Pittsburgh, Pa.; Zeonex Cyclo OlefinPolymer by Zeon Chemicals L.P. of Louisville, Ky.) or other material.Although acrylics and polycarbonates may be used to form theconcentrator 40, UV radiation from the COB LEDs 14 can cause clouding orreduced transparency over time in certain acrylics and polycarbonates,degrading the optical properties of the concentrator 40 such that thewarning signals become less apparent to an observer remote from thelight bar. In addition, the ON-OFF cycling of the COB LEDs 14 to createwarning signals subjects the concentrator 40 to intermittent heat outputby the COB LEDs 14. This results in repeated heating and cooling of theconcentrator which causes repeated thermal expansion and contraction ofthe concentrator. Such heat cycling can cause stress fractures over timein certain acyrlics and polycarbonates, further degrading the opticalproperties of the concentrator such that the warning signals become lessapparent to an observer remote from the light bar. It has been foundthat polycarbonate resins, such as LED-2245 or LED-2045 noted above,maintain their optical properties and are resistant to such opticaldegradation, thereby permitting such resins to be used in light bars torepeatedly generate acceptable warning signals that continue over timeto be apparent to an observer remote from the light bar. Theconcentrator 40 and the collector 42 may be formed as an integralconstruction or as separate components by compression molding, injectionmolding, or other molding techniques. The concentrator 40 and thecollector 42 may be molded within a tolerance of 0.0005 inches wherebyshrinkage of the concentrator 40 and the collector 42 after molding isminimized so that the optical properties of the concentrator 40 and thecollector 42 when molded is substantially the same as the opticalproperties of the concentrator 40 and the collector 42 after themolding. Other ways of making the optic component, including theconcentrator 40 and the collector 42, are within the scope of theinvention. For example, one or more optic components (e.g., three opticcomponents) may be formed together as a single, one-piece unit. It isunderstood that the optical concentrator 40 and optical collector 42 maybe formed in other ways and from other material without departing fromthe scope of the present invention.

Referring to FIG. 2, the optical collimator 44 is secured at an open endof a casing 52 that is secured to the heat sink 20 and encloses theoptic component 28 (e.g., the concentrator 40 and the collector 42) andthe circuit board 22. The collimator 44 is configured to make the lightfrom the collector 42 more aligned in a specific direction. Thecollimator 44 is spaced apart from the output surface of the collector42. A cross-sectional area of the output surface of the collector 42 isless than a cross-sectional area of an input surface of the collimator44. In one example, the cross-sectional area of the output surface ofthe collector 42 is less than the cross-sectional area of the inputsurface of the collimator 44. The collimator 44 may be formed from thesame material as the concentrator 40 and the collector 42. Thecollimator 44 may be formed from a homogenous material that is resistantto UV radiation, such as acrylic or polycarbonate or other material(e.g., Makrolon® LED-2245 or LED-2045 polycarbonate resin, each by BayerMaterialScience AG of Pittsburgh, Pa.; Zeonex Cyclo Olefin Polymer byZeon Chemicals L.P. of Louisville, Ky.). The collimator 44 may be formedby compression molding, injection molding or through other moldingtechniques. For example, the collimator 44 may be molded within atolerance of 0.0005 inches whereby shrinkage of the collimator 44 aftermolding is minimized so that the optical properties of the collimator 44when molded is substantially the same as the optical properties of thecollimator 44 after the molding

Light transmitted out of the collimator 44 comprises a spatially uniformbeam. In the illustrated embodiment, an optical diffuser 54 is providedbetween the collimator 44 and an end cap 55 of the light head 12 toreceive the light from the collimator and redistribute the light into adesired output pattern. The diffuser 54 may be a holographic diffuser,such as a holographic elliptical diffuser, formed of a polycarbonatematerial. In the illustrated embodiment, the diffuser 54 is formed as aseparate component and secured to the light head 12 by sandwiching itbetween the collimator 44 and the end gap 55. In another embodiment, theholographic elliptical diffuser 54 (e.g., textured polycarbonatematerial) can be molded onto the interior surface of a light head cap55. Other ways of forming the optical diffuser, such as a holographicelliptical diffuser, and securing the diffuser to the light head iswithin the scope of the present invention.

In one example, the diffuser 54 (e.g., a holographic diffuser such as aholographic elliptical diffuser) is configured to produce an outputpattern that is horizontally diverging at a horizontal angle which isgreater than a horizontal divergence angle of the spatially uniformbeam. The diffuser 54 may also be configured to produce an outputpattern that is vertically diverging at a vertical angle which isgreater than a vertical divergence angle of the spatially uniform beam.In another example, the diffuser 54 is configured to produce an outputpattern that partially redistributes or transmits the transmitted lightso that some of the transmitted light is redistributed or transmitted bythe diffuser 54 and some of the transmitted light is not redistributedor transmitted by the diffuser 54. In yet another example, the diffuser54 has an opening positioned over the collimator 44 so that some of thetransmitted light is redistributed or transmitted by the diffuser 54 andsome of the transmitted light is not redistributed or transmitted by thediffuser 54 and passes through the opening. In another example, thediffuser 54 is configured to produce an output pattern that comprises asubstantially rectangular pattern when viewed by an observer remote fromthe light bar 10. The diffuser 54 may be a holographic ellipticaldiffuser having a diffusing angle greater than 45 degrees, and morepreferably, within a range of greater than 45 degrees to about 80degrees, more preferably within a range of about 55 degrees to about 70degrees, and still more preferably, about 60 degrees.

In one example (e.g., FIGS. 3 and 4), the COB LED(s) 14 in a first lightemitting area 24 of the light head 12 may constitute a first COB LED(s)14 configured to emit light having a first color in one wavelengthrange, and the COB LED(s) 14 in a second light emitting area 24 mayconstitute a second COB LED(s) 14 configured to emit light having asecond color different than the first color in a second wavelength rangedifferent than the first wavelength range. Moreover, the COB LED(s) 14in a third light emitting area 24 may constitute a third COB LED(s)configured to emit light having a third color different than the firstand second colors in a third wavelength range different than the firstand second wavelength ranges. It is understood that there may be anynumber of different COB LEDs 14 (i.e., two or more) that are configuredto emit light having a different color and wavelength range than thoseof the other COB LEDs within the same light head 12. It is alsounderstood that the COB LEDs in two or more light emitting areas may beconfigured to emit light having substantially the same color andsubstantially the same wavelength range.

The microcontroller 18 may be configured to do one or more of thefollowing: selectively energize the first COB LED(s) 14 to createwarning light signals including light having the first color;selectively energize second COB LED(s) 14 to create warning lightsignals including light having the second color; and selectivelyenergize both the first COB LED(s) 14 and the second COB LED(s) 14simultaneously to create warning light signals including light havingthe first color and the second color.

The microcontroller 18 may be configured to energize only one of thefirst COB LED(s) 14 and the second COB LED(s) 14 and to notsimultaneously energize both the first COB LED(s) 14 and the second COBLED(s) 14.

The microcontroller 18 may be configured to energize the first COBLED(s) 14 and the second COB LED(s) 14 in a first pattern to provide atraffic directing signal, and to energize the first COB LED(s) 14 andthe second COB LED(s) 14 in a second pattern to provide a warningsignal.

The microcontroller 18 may be configured to energize the light heads 12in a first pattern and a different second pattern. During the firstpattern, the microcontroller energizes the first COB LEDs 14 of a firstselected set of the light heads 12 and the second COB LEDs 14 of thefirst selected set of light heads 12 are not energized. During thesecond pattern, the microcontroller energizes the second COB LEDs 14 ofa second selected set of the light heads 12 and the first COB LEDs 14 ofthe second set of light heads 12 are not energized.

The microcontroller may be configured to modulate energization of thefirst COB LED 14 and the second COB LED 14 to create at least twodifferent warning light signals sequentially presented over apredetermined period of time.

In one example using the above arrangement of the optical concentrator40, the optical collector 42 and the optical collimator 44, one COB LED14 on the circuit board 22 can produce an output signal having morelumens after it is transmitted through the optic component 28 than anoutput signal if the COB LED 14 was replaced with a correspondingpre-packaged LED. For example, a red COB LED can emit more than 50lumens; a blue COB LED can emit more than 30 lumens; an amber COB LEDcan emit more than 40 lumens; and a white COB LED can emit more than 100lumens. It is believed that the greater lumen output using COB LEDs isdue to ability to drive the COB LEDs harder than the pre-packaged LEDswithout causing early failure because the heat from the COB LEDs can bedissipated more efficiently. Moreover, the use of the opticalconcentrator 40, the optical collector 42 and the optical collimator 44increases the overall output of the optical component.

In another example (e.g., FIGS. 3B and 4B), a plurality of N COB LEDs 14are positioned in a single light emitting area 24 on the circuit board22 and associated with one of the optic components 28, where N is aninteger greater than 1. The optic component 28 comprises a singleoptical path for combining the light from the N COB LEDs 14 to create awarning light signal. The total transmitted light from the opticcomponent 28 is greater than the total transmitted light if the N COBLEDs 14 were replaced with corresponding pre-packaged LEDs. In thisexample, the COB LEDs 14 in each light emitting area 24 may beconfigured to emit light of different colors in different wavelengthranges. For example, a single light emitting area 24 may include one ormore first COB LEDs configured to emit light having a first color in onewavelength range, and one or more second COB LEDs 14 configured to emitlight having a second color different than the first color in a secondwavelength range different than the first wavelength range. Moreover,for example, the same light emitting area 24 may include one or morethird COB LEDs configured to emit light having a third color differentthan the first and second colors in a third wavelength range differentthan the first and second wavelength ranges. Each of the first, secondand third COB LEDs 14 within the same light emitting area 24 may beindependently controlled and operated to produce a desired light signalin the same way as described above where each light emitting area has adifferent COB LED(s) than the other light emitting area(s). It isunderstood that there may be any number of different COB LEDs 14 (i.e.,two or more) that are configured to emit light having a different colorand wavelength range than those of the other COB LEDs within the samelight emitting area 24. It is also understood that the COB LEDs in onelight emitting areas may be configured to emit light havingsubstantially the same color and substantially the same wavelengthrange.

The microcontroller may be configured to selectively energize the COBLEDs 14 with a pulse width modulated signal having a reduced duty cycleof less than 100%. The reduced duty cycle provides transmitted light ofreduced lumens compared to the lumens provided at a 100% duty cyclewhereby night blindness is minimized when the COB LED 14 is energizedwith the reduced duty cycle and the transmitted light at the reducedduty cycle meets or exceeds minimum requirements for a warning lightsignal.

In one example, one or more of the COB LEDs 14 has one or more of thefollowing: a lumens per amp output greater than the lumens per ampoutput of a corresponding pre-packaged LED; a lumens output greater thanthe lumens output of a corresponding pre-packaged LED; a thermalresistance less than the thermal resistance of a correspondingpre-packaged LED; dissipation of heat to the heat sink 20 at a higherrate than the dissipation of heat to a heat sink from a correspondingpre-packaged LED; a maximum driving current greater than a maximumdriving current of a corresponding pre-packaged LED; and a heat transferflux density greater than a heat transfer flux density of acorresponding pre-packaged LED.

In one example, one or more of the COB LEDs 14 has one or more of thefollowing characteristics: more efficient than a correspondingpre-packaged LED in that the COB LED 14 produces more lumens per amp; agreater lumens output than the lumens output of a correspondingpre-packaged LED; a lower thermal resistance than a correspondingpre-packaged LED; a higher heat dissipation rate to the heat sink 20than a corresponding pre-packaged LED; a greater maximum driving currentof than a maximum driving current of a corresponding pre-packaged LED;and a higher heat transfer flux density than a correspondingpre-packaged LED.

Referring to FIG. 8, the light bar housing 16 includes a plurality ofhousing modules mounted on a base, generally indicated at 82. In oneembodiment, the housing modules may come in three standard types: anoutboard type 56 a, a short center type 56 b, and a long center type 56c. The short center type 56 b is the same configuration as the longcenter type 56 c except that it has a shorter length—respective lengthsextending along the length of the light bar 10. In one example, theoutboard housing module 56 a may have a length of about 12.5 in, theshort center housing module 56 b may have a length of about 7.0 in, andthe long center housing module 56 c may have a length of about 11.0 in.The use of two different center housing modules 56 b, 56 c havingdifferent lengths allows for the assembly of light bars having thefollowing exemplary lengths: 23.0 in; 35.0 in; 44.0 in; 47.0 in; 52.0in; 58.0 in; 70.0 in; 82 in; and 94.0 in. The housing modules 56 a, 56b, 56 c may have other lengths without departing from the scope of thepresent invention. The light bar 10 illustrated in FIG. 8 comprises twooutboard housing modules 56 a, two short center housing modules 56 b,and one long center housing module 56 c. In this embodiment, light bar10 may include other types of the light sources besides those having COBLEDs, including but not limited to light sources including pre-packagedLEDs, incandescent lamps, and halogen lamps.

Referring still to FIG. 8, each housing module 56 a, 56 b, 56 c,regardless of its type, comprises a lens cover, generally indicated at58, secured to a platform, generally indicated at 60. The lens cover 58has a top portion 62 and a transparent lens portion 64 extendingdownward from the top portion. The top portion 62 is generally opaqueand functions as a solar barrier that blocks UV rays to lessen heatwithin the module 56 a, 56 b, 56 c and prevent UV degradation of wiringand the light heads 12 in the module. (The top portion 62 is shown asbeing transparent for illustrative purposes only.) The lens portion 64is generally transparent and is positioned in generally opposingrelationship with the light head 12 when the lens cover 58 is secured tothe platform 60. The lens cover 58 may be formed in a two-step moldingprocess, such as by first molding the top portion with a UV impermeablematerial or composition, and then overmolding the top portion withtransparent material or composition to form the lens portion 64.

Referring to FIGS. 9 and 10, the lens cover 58 includes a plurality ofrib members 66 extending downward on the inner side of the lens portion64. Each rib member 66 includes a finger 70 that is receivable in achannel 72 extending adjacent to the perimeter of the platform 60. Thechannel 72 is defined by inner and outer upstanding projections 74, 76,respectively, extending upward from the platform 60. The innerupstanding projections 74 of the short and long center housing modules56 b, 56 c do not extend along the opposite longitudinal ends of theplatforms 60, and the inner upstanding projections of the outboardhousing modules 56 a do not extend along the inner ends of theplatforms. Instead, the outer upstanding projections 76 of the short andlong center housing modules 56 b, 56 c extend as bridge members alongthe opposite longitudinal ends of the platforms, and the outerupstanding projections of the outboard housing modules extend as bridgemembers 78 on the inner longitudinal ends of the platforms. A gasket 79(FIG. 10) is secured to an outside of the outer projection 76, includingthe respective bridge members 78. The gasket may be a ribbed (e.g.,double ribbed) gasket made from rubber or other compressible materialand may be attached to the outer projection 76 by pressure sensitiveadhesive or in other ways without departing from the scope of thepresent invention. When the lens cover 58 is secured to the platform 60,the gasket forms a seal between the lens portion 64 of the lens coverand the outer upstanding projection 76 on the platform to preventmoisture and debris from entering the housing module 56 a, 56 b, 56 c.Moreover, because the fingers 70 of the rib members 66 are received inthe channel 72 on the platform 60, the rib members prevent bowing orbending of the lens portion 64 so that the lens portion compresses thegasket and a tight seal is formed and maintained between the lens coverand the platform. The lens cover 58 is secured to the platform 60 byfasteners (e.g., screws) extending through openings in the opaque topportion 62 and into threaded openings in four securement posts 80 (FIGS.8, 13 and 14) extending upward from the platform.

As shown best in FIG. 8, each of the housing modules 56 a, 56 b, 56 c ismounted along the length of the elongate base, generally indicated at82, and the base 82 is in turn secured to spaced apart mounting feet,which secure the light bar 10 to the vehicle. As shown best in FIGS.10-12, channels 83 on the underside of the base 82 receive a head of afastener (e.g., bolt or nut) that secures a mounting foot MF to thebase. The platform 60 defines a large opening 84 (FIG. 8) for receivingthe base 82 when the platform is positioned on top of the base.Referring to FIGS. 9, 11 and 12, the base 82 includes a pair of spacedapart, threaded inner channels 86 and a pair of spaced apart, threadedouter channels 88. The inner and outer channels 86, 88 extend along thelength of the base 82. The base 82 may be extruded aluminum, or may beother materials and may be formed in other ways without departing fromthe scope of the present invention.

Referring to FIG. 13, the inner channels 86 threadably receive fasteners(e.g., screws, not shown) to secure a control board 90 to the base 82.The control board 90 is described in more detail below. The outerchannels 88 threadably receive fasteners (e.g., screws, not shown), andeach channel is used to secure a brace 92 and/or the light heads 12 tothe base 82. The brace 92 includes openings 94 spaced apart along thelength of the brace and a flange 95 that engages an edge 96 formed onthe platform 60. A bracket 97 extending rearward from each of the frontand rear light heads 12 has openings that align with the openings in thebrace 92. One or more fasteners received through the aligned openingsare threaded into the respective outer channel 88 to secure the frontand rear light heads 12 to the brace 92, and to secure the platform 60to the base 82. The corner light heads 12 and alley light head 12 alsoinclude brackets 98 (FIG. 8) for securing the respective light heads toeither the base 82 or to the platform 60. Other ways of securing thelight heads 12 to the light bar 10 do not depart from the scope of thepresent invention.

As shown in FIG. 13, the microcontroller 18 is mounted on the controlboard 90. Other electrical components are also mounted on the controlboard, including: computer chips acting electrical switches,over-current protection devices, and connectors to provide control andoutput wire attachment. The control board 90 may also be referred to asa “central controller” or “lightbar controller” in the art. Each lighthead 12 is electrically connected to the control board 90, and thus themicrocontroller 18, by a wire-to-board connection. More specifically,each light head 12 includes an electrical wire-to-board connector 102for electrically connecting the light head to a mateable wire-to-boardconnector 104 (FIG. 14) on the control board 90. The wire-to-boardconnectors 102, 104 allow for quick and easy electrical connection ofthe light heads 12 to the control board 90, and thus to themicrocontroller 18. Accordingly, each of the light heads 12 is easilyreplaceable by removing the fasteners that secure the light head to therespective housing module 56 a, 56 b, 56 c and disconnecting thewire-to-board connectors 102, 104. A new one of the light heads 12 isthen easily mounted on the light bar 10 and the wire-to-board connectors102, 104 are connected to connect the new light head to the controlboard 90 and to the microcontroller 18.

Having described embodiments of the invention in detail, it will beapparent that modifications and variations are possible withoutdeparting from the scope of the invention defined in the appendedclaims.

When introducing elements of the present invention or the illustratedembodiment(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As various changes could be made in the above constructions, products,and methods without departing from the scope of the invention, it isintended that all matter contained in the above description and shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:
 1. A light bar comprising: an elongate base havingopposite longitudinal ends and a length extending between thelongitudinal ends; first and second outboard housing modules removablysecured to the base adjacent to the opposite longitudinal ends of thebase, at least one light head being disposed in each of the first andsecond outboard housing modules; a short center module removably securedto the base between the first and second outboard housing modules, theshort center module having a length extending along the length of thebase, at least one light head being disposed in the short center module;a long center module removably secured to the base between the first andsecond outboard housing modules, the long center module having a lengthextending along the length of the base, at least one light head beingdisposed in the long center module; wherein the length of the longcenter module is greater than the length of the short center module,wherein a length of each of the first and second outboard housingmodules is greater than the length of the short center module.
 2. Alight bar comprising: an elongate base having a length extending betweenopposite longitudinal ends; a plurality of housing modules secured alongthe length of the base, each housing module including: at least onelight head, a platform on which said at least one light head is mounted,a lens cover secured to the platform, the lens cover having a topportion that is substantially impervious to ultraviolet radiation, and alens portion extending downward from the top portion in generallyopposing relationship with said at least one light head.
 3. A light baras set forth in claim 2 wherein each housing module further includes agasket secured generally adjacent to a perimeter of the platform,wherein the lens portion of the lens cover compresses the gasket to forma watertight seal between the lens cover and the platform.
 4. A lightbar as set forth in claim 3 wherein the platform includes an upstandingprojection extending generally adjacent to the perimeter of theplatform, wherein the gasket is secured to the upstanding projection. 5.The light bar set forth in claim 2, wherein the top portion of the lenscover is generally opaque, and the lens portion is generallytransparent.